# Elastic collision between bowling ball and tennis ball

1. Oct 18, 2012

### bdh2991

1. The problem statement, all variables and given/known data

9.6 A table-tennis ball is thrown at a stationary bowling ball. The
table-tennis ball makes a one-dimensional elastic collision and bounces back
along the same line. Compared with the bowling ball after the collision, does
the table-tennis ball have (a) a larger magnitude of momentum and more
kinetic energy, (b) a smaller magnitude of momentum and more kinetic
energy, (c) a larger magnitude of momentum and less kinetic energy, (d) a
smaller magnitude of momentum and less kinetic energy, or (e) the same
magnitude of momentum and the same kinetic energy?

2. Relevant equations

p = mv
k = 1/2 m v^2

3. The attempt at a solution

2. Oct 19, 2012

### frogjg2003

You have a light moving object (tennis ball) impact and reflect from a heavy stationary object (bowling ball). Think in terms of conservation of momentum and energy. Remember, momentum is a vector so it has a magnitude and direction.
Let's say the ball was moving in the positive direction, then after the impact, its moving in the negative direction. What has to happen to conserve momentum?